Apparatus and method for pulsed laser deposition of materials on wires and pipes

Abstract

Methods and apparatuses are disclosed which allow uniform coatings to be applied by pulsed laser deposition (PLD) on inner and outer surfaces of cylindrical objects, such as rods, pipes, tubes, and wires. The use of PLD makes this technique particularly suitable for complex multicomponent materials, such as superconducting ceramics. Rigid objects of any length, i.e., pipes up to a few meters, and with diameters from less than 1 centimeter to over 10 centimeters can be coated using this technique. Further, deposition is effected simultaneously onto an annular region of the pipe wall. This particular arrangement simplifies the apparatus, reduces film uniformity control difficulties, and can result in faster operation cycles. In addition, flexible wires of any length can be continuously coated using the disclosed invention.

What is claimed is:  
     
       1. A method for depositing at least one material from a target surface onto an inner wall of a pipe, said method comprising: 
       passing a pulsed laser beam through at least one lens whereby said laser beam is caused to form an annular ring cross-section on the target surface of said at least one material,  
       ablating said target surface with said laser beam, wherein the target surface is located within a pipe to be internally coated and is at an inclination with respect to the symmetry axis of the pipe,  
       moving the pipe, the target, or both to produce motion between the pipe and the target so that said inner wall is coated with said material along a length of said pipe, and  
       said method occurring in a vacuum or in a reduced-pressure atmosphere, optionally other than air.  
     
     
       2. The method according to  claim 1 , wherein said at least one material is a multicomponent material. 
     
     
       3. The method according to  claim 2 , wherein said multicomponent material is a ceramic oxide. 
     
     
       4. The method according to  claim 1 , wherein said at least one material is a carbide, nitride or diamond-like carbon. 
     
     
       5. A method for uniformly depositing at least one material from a target surface onto an inner wall of a pipe or rod that is in a symmetric configuration with the axes of a laser beam and said target surface, said method comprising: 
       passing an axially symmetric, pulsed laser beam through optics that shape the beam into a cone or a truncated cone, said optics comprising at least one negative conical lens and at least one spherical converging lens, wherein the symmetry axes of said target surface and said lenses are collinear,  
       converging said laser beam towards the target surface, such that the beam has a substantially annular cross-section on the target surface.  
       ablating the target surface with the laser beam, whereby the beam produces a plume of evaporate material having a conical shape,  
       placing said rod or pipe to be coated in a position whereby a longitudinal axis of said rod or pipe is coincident with said symmetry axes such that the rate of evaporate material incident on said inner wall is substantially the same for every direction in said plume, and  
       moving said rod or pipe, said target surface, or both, to produce motion between the pipe and the target surface so that said inner wall is coated with said material along a length of said rod or pipe,  
       wherein said inner wall is optionally heated above room temperature.  
     
     
       6. The method of  claim 5 , wherein the step of converging said laser beam towards the target surface further comprises converging said laser beam so that an annular ring forms on the target surface. 
     
     
       7. The method of  claim 6 , wherein the step of ablating the target surface further comprises ablating the target surface having a conic shape including a tip, wherein said tip is positioned with said annular ring so that the laser beam does not impinge upon said tip.